DESCRIPTION: (Applicant's Description) A major scientific challenge in cancer biology is the identification and characterization at molecular level of the cellular changes in various neoplastic diseases. Critical to the success of this endeavor is the development and implementation of new tools for rapid and sensitive protein identification and characterization of their post- translational modifications. High sensitivity of mass spectrometry (MS) has become an invaluable tool for such studies. The major goal of the proposed "NCI Mass Spectrometry Shared Resource for Proteomics and Protein Analysis" is to expand and upgrade the capacity and sensitivity of our mass spectrometry facility and to apply state-of-the-art MS technologies to critical protein analysis involved in cancer research, strengthening cancer research program at Mount Sinai. The specific aims of this Shared Resource are: 1. To provide rapid, cost-effective, and high-quality MS service for NCI and other cancer-oriented investigators at Mount Sinai and other NCI- funded investigators in the New York City in order to perform cutting- edge research in which new mass spectrometric technologies are used to solve important biochemical and biomedical problems. 2. To transfer newly developed MS technology from my research laboratory to the NCI Shared Resource and expand the capacity and upgrade the sensitivity of mass spectrometry techniques for assisting NCI-funded and other cancer-oriented investigators. 3. To educate NCI-funded investigators, other cancer-oriented scientists, and their staffs on using MS for protein analysis in cancer biology.